There are many different systems of greenhouse humidifier systems you can chose from. The research can be overwhelming at first but when you outline the benefits verses the cons you can see the differences clearly.  Maintenance fee is a positive option to look for, small sizes in droplets, and the pressure the droplets are released.  Those are important key points to consider for a successful humidifier system.  A programmable systems is also a great benefit.  The time and energy that is put into a successful greenhouse can be benefited from these product features.  It will certainly help it become successful.